You don't believe in God or scripture so you are hardly going to take anything to do with it seriously. But again I will play.
Like I said we have a snap shot from scripture about certain changes that occurred at the fall-flood and Tower of babel. This does not mean it was all of the changes, just the ones that God pointed out because as I said scripture is not a book about science, its a book about truth.
Before the fall there was no death.
Death meaning creatures with a soul and life blood, that I apparently have to repeat every time to prevent someone jumping in with nonsense about plants being chewed and bugs being steeped on. Surely our model is not so hard that you all can't remember some of the basic facts.
Sin brought in death. Only man can sin. This happened shortly after creation.
Man was created from the ground and brought to life by God. Already we have a vastly different world set up going on.
The fall changed the biology and behaviors of animals, corrupting them from their original purpose. Many herbivores became carnivores, many helpful parasites became destroying parasites.
The fall changed the plants, again corrupting them and changing them. Thorns and thistles came with the curse.
The flood caused the vapour canopy to fall down, it also caused an ice age and a permanent change in climate and changed the amount of Cosmic Rays reaching the earth.
These are the type of changes that I am talking about.